Police, soldiers, firefighters, and other first responders often must enter a building, a structure, or other places with little or no knowledge about potential dangers (e.g., lurking criminals/terrorists or enemy combatants, leaking flammable gas or radio active substance) that may be present in such locations. Search and rescue, law enforcement or military operations would benefit greatly if information about the interior of such locations can be known before entry. The existing surveillance systems are too complex and expensive to be accessible to frontline responders both in the developed and developing world.